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RE: Shexc tied to XML?

From: Irene Polikoff <irene@topquadrant.com>
Date: Wed, 6 Aug 2014 08:57:30 -0400
To: "'Sandro Hawke'" <sandro@w3.org>, "'Holger Knublauch'" <holger@topquadrant.com>, <public-rdf-shapes@w3.org>
Message-ID: <081b01cfb175$fc157b70$f4407250$@topquadrant.com>
Sandro,

I believe there is an issue that is somewhat different - why do we need yet another new syntax that is separate from RDF and uses different paradigm and semantics?

>From the data model perspective, RDF was never a kind of XML. It can be serialized as XML, but it has a different data model. This difference was, perhaps, obvious to the standard committee and they never thought anyone would be confused or that this confusion would be an issue. 

In reality, this was, however,  a big issue. It was very difficult for other people to understand what RDF was without a lot of education that had to change the assumptions they quickly made after first getting to know about RDF. First impressions are hard to change. Things became easier after Turtle became better known as the way to serialize and RDF/XML faded into background as just one (lesser used) serialization. I can attest to this after being involved in training hundreds of people over the last 10 years in Semantic Web technologies stack.

So, another point/lesson/issue is that it is very easy to cause a considerable unnecessary confusion and that confusion is a serious obstacle to adoption of a technology.

Irene

-----Original Message-----
From: Sandro Hawke [mailto:sandro@w3.org] 
Sent: Wednesday, August 06, 2014 8:31 AM
To: Holger Knublauch; public-rdf-shapes@w3.org
Subject: Shexc tied to XML?

On August 4, 2014 11:22:28 PM EDT, Holger Knublauch <holger@topquadrant.com> wrote:
>On 8/5/2014 12:27, Eric Prud'hommeaux wrote:
>>
>>
>> On Aug 5, 2014 3:52 AM, "Holger Knublauch" <holger@topquadrant.com 
>> <mailto:holger@topquadrant.com>> wrote:
>> >
>> >
>> > On 8/5/14, 11:23 AM, Karen Coyle wrote:
>> >>
>> >> Holger,
>> >>
>> >> Yes, your example is most likely understandable by anyone who does
>
>> some coding, without being a "semantic web engineer." Now the
>question
>> is: who creates this and how? And do they have to be fully versed in
>RDF?
>> >
>> > To be honest, I believe the modern reality is that people create
>> those things using copy and paste from sites such as StackOverflow. 
>> And that's not necessarily bad, and we all do it. As long as the 
>> common patterns are well documented snippets, nobody needs to 
>> understand the formal underpinnings, and the syntax allows them to 
>> ignore the attributes that they don't need. A good example of how to 
>> present this is the schema.org <http://schema.org> documentation, 
>> which includes copy-able snippets in various formats.
>> >
>> > And I like the analogy of a gateway "drug", because anyone who
>cares
>> to look deeper may have an easier path to understanding the RDF model
>
>> too. This is IMHO more useful than pretending that RDF was XML and
>use
>> RELAX-NG as the starting point.
>>
>> Assuming that this is a reference to ShEx, can you explain how it 
>> pretends that RDF is XML?
>>
>
>ShEx doesn't explicitly mention XML apart from comparing it to XML 
>Schema in the introduction of the primer. But the SHEXc syntax is 
>modeled after RelaxNG Compact Syntax

Is it?    To me it looks like someone combined data structure definitions from any language that has such things (Pascal, C, Java, Go, ....) with the Kleene operators, known to every programmer from EBNF and RegExps.

Eric may have been thinking about relaxng, but the design makes prefect sense and seems completely familiar to some of us not steeped in relaxng.

>  may therefore come to
>the
>conclusion that this is just a variation of XML (XML Schema). 
>Furthermore, it has one dedicated Start rule that is comparable to the 
>root of an XML document.
>
>My concern is that we had this confusion before: When RDF and OWL were 
>standardized, they came with RDF/XML syntax only, and people thought 
>this semantic web is just another kind of xml.

In those days RDF was in fact a kind of XML.    I mean, the only interoperable way to exchange it was RDF/XML.    To this day .rdf files are still XML.

It seems a bit like you're concerned that because a movie has an action hero in it, people who don't like Arnold Schwarzenegger's politics will avoid it, just because at one point he was a very popular star of action movies.

To my eye, there is no connection between shexc and XML.

    - Sandro

> But a complicating kind
>of XML, where the idea of graphs was hidden behind rdf:ID and rdf:about
>
>attributes.
>
>This is more about first impressions than rational facts.
>
>Holger
Received on Wednesday, 6 August 2014 12:58:00 UTC

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